Alpha Ceti
Template:Short description Template:About Template:Starbox begin Template:Starbox image Template:Starbox observe Template:Starbox character Template:Starbox astrometry Template:Starbox detail Template:Starbox catalog Template:Starbox reference Template:Starbox end Alpha Ceti (α Ceti, abbreviated Alpha Cet, α Cet), officially named Menkar Template:IPAc-en,<ref name=Kunitzsch>Template:Cite book</ref><ref name="IAU-CSN">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> is the second-brightest star in the constellation of Cetus. It is a cool luminous red giant estimated to be about 250 light years away based on parallax.
NomenclatureEdit
Alpha Ceti is the star's Bayer designation. It has the traditional name Menkar, deriving from the Arabic word منخر manħar "nostril" (of Cetus). In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)<ref name="WGSN">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016<ref name="WGSN1">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> included a table of the first two batches of names approved by the WGSN; which included Menkar for this star.
This star, along with γ Cet (Kaffaljidhma), δ Cet, λ Cet (also Menkar), μ Cet, ξ1 Cet and ξ2 Cet were Al Kaff al Jidhmah, "the Part of a Hand".<ref>Star Name - R.H. Allen p.160</ref>
In Chinese, {{#invoke:Lang|lang}} ({{#invoke:Lang|lang}}), meaning Circular Celestial Granary, refers to an asterism consisting of α Ceti, κ1 Ceti, λ Ceti, μ Ceti, ξ1 Ceti, ξ2 Ceti, ν Ceti, γ Ceti, δ Ceti, 75 Ceti, 70 Ceti, 63 Ceti and 66 Ceti. Consequently, the Chinese name for α Ceti itself is {{#invoke:Lang|lang}} ({{#invoke:Lang|lang}}, Template:Langx.)<ref>Template:In lang AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 11 日 Template:Webarchive</ref>
CharacteristicsEdit
Despite having the Bayer designation α Ceti, at visual magnitude 2.54 this star is actually not the brightest star in the constellation Cetus. That honor goes instead to Beta Ceti at magnitude 2.04. Menkar is a red giant with a stellar classification of M1.5 IIIa.<ref name=aaa489_3_1271/> It has more than twice the mass of the Sun<ref name=aaa460_3_855/> and, as a giant star, has expanded to about 100 times the Sun's radius.<ref name="Soubiran2024"/> The large area of the photosphere means that it is emitting about 1,765 times as much energy as the Sun, even though the effective temperature is only Template:Val (compared to Template:Val on the Sun).<ref name="Soubiran2024"/> The relatively low temperature gives Menkar the red hue of an M-type star.<ref name=csiro/>
Menkar has evolved from the main sequence after exhausting the hydrogen at its core. It has also exhausted its core helium, becoming an asymptotic giant branch star,<ref name=eggen/> and will probably become a highly unstable star like Mira before finally shedding its outer layers and forming a planetary nebula, leaving a relatively large white dwarf remnant.<ref name=kaler/> It has been observed to periodically vary in brightness, but only with an amplitude of about one hundredth of a magnitude.<ref name=koen/>
NamesakesEdit
Menkar (AK-123) was a United States Navy Crater class cargo ship named after the star.